Last major update issued on May 11, 2014 at 06:25 UTC.
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[Solar cycles 23-24 (last update May 1, 2014)] [Cycle 24 progress (last update May 1, 2014) ]
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[Presentation 3rd SSN Workshop, Tucson, 2013 (pdf)]
The geomagnetic field was quiet to unsettled on May 10. Solar wind speed at SOHO ranged between 327 and 383 km/s. A disturbance, likely associated with CH616, began late in the day.
Solar flux at 20h UTC on 2.8 GHz was 150 (increasing 12.9 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 149.2. The Potsdam WDC planetary A index was 7 (STAR Ap - based on the mean of three hour interval ap indices: 6.8). Three hour interval K indices: 23111022 (planetary), 23222222 (Boulder).
The background x-ray flux is at the class B8 level.
At the time of counting spots (see image time), spots were observed in 17 active regions in 2K resolution (SN: 331) and 16 active regions in 1K resolution (SN: 245) SDO images on the visible solar disk.
Region 12053 [N09W42] decayed slowly and quietly.
Region 12054 [S13W11] decayed slowly and quietly.
Region 12055 [N11E04] displayed no major changes and was mostly quiet. An M class flare is possible.
Region 12056 [N05E17] has minor polarity intermixing. An M class flare is still possible.
Region 12057 [N15E27] was quiet and stable.
Region 12058 [S11E42] displayed only minor changes and could produce C flares.
New region 12059 [N00E21] was finally split off from AR 12056 by SWPC.
Spotted regions not numbered (or interpreted differently) by SWPC:
S3386 [S19W56] was quiet and stable.
S3394 [S20W18] reemerged with penumbra spots.
S3404 [N13W08] reemerged with penumbra spots.
S3405 [N09E27] developed slowly as new flux emerged.
S3407 [S16E53] has polarity intermixing and could produce a minor M class flare.
New region S3411 [S13E16] emerged with penumbra spots.
New region S3412 [N21W38] emerged with penumbra spots early in the day and decayed later on.
New region S3413 [S23E80] rotated into view.
New region S3414 [S06W15] emerged with several spots.
New region S3415 [N02E30] emerged with penumbra spots.
May 8-10: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
Coronal hole history (since October
Compare today's report to the situation one solar rotation ago: 28 days ago 27 days ago 26 days ago
A small southern hemisphere coronal hole (CH616) was in an Earth facing position on May 7. A southern hemisphere coronal hole (CH617) could rotate into an Earth facing position on May 12.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over upper middle latitudes is poor. Propagation on long distance northeast-southwest paths is poor to fair.
The geomagnetic field is expected to be quiet to active on May 11 due to effects from CH616 and quiet on May 12-13.
|Coronal holes (1)||Coronal mass ejection (2)||M and X class flares (3)|
1) Effects from a coronal hole could reach Earth within the
next 5 days. When the high speed stream has arrived the color changes to
2) Effects from a CME are likely to be observed at Earth within 96 hours.
3) There is a possibility of either M or X class flares within the next 48 hours.
Green: 0-30% probability, Yellow: 30-70% probability, Red: 70-100% probability.
(Click on image for 2K resolution) Compare to the previous day's image. 0.5K image
When available the active region map has a coronal hole polarity overlay where red (pink) is negative and blue is positive.
Data for all numbered solar regions according to the Solar Region Summary provided by NOAA/SWPC. Comments are my own, as is the STAR spot count (spots observed at or inside a few hours before midnight) and data for regions not numbered by SWPC or where SWPC has observed no spots. SWPC active region numbers in the table below and in the active region map above are the historic SWPC/USAF numbers.
|Active region||Date numbered
|Spot count||Location at midnight||Area||Classification||SDO / HMI 4K continuum
image with magnetic polarity overlay
|Total spot count:||45||161||85|
|Sunspot number:||125||331||245||(total spot count + 10 * number of spotted regions)|
|Weighted SN:||86||208||133||(Sum of total spot count + classification weighting for each AR. Classification weighting: X=0, R=3, A/S=5, H/K=10)|
|Relative sunspot number (Wolf number):||81||116||135||k * (sunspot number). k = 0.6 for SWPC, k = 0.35 for MSN 2K, k = 0.55 for MSN 1K (MSN=Magnetic Sunspot Number)|
|Month||Average solar flux||International sunspot number
|Smoothed sunspot number||Average ap
|2013.11||148.3||145.1||77.6||(75.6 projected, +0.6)||5.68|
|2013.12||147.7||143.1||90.3||(76.6 projected, +1.0)||4.68|
|2014.01||157.4||152.4||82.0||(77.6 projected, +1.0)||5.44|
|166.3||102.8 (cycle peak)||(77.4 projected, -0.2)||10.70|
|2014.03||149.9||148.5||92.2||(77.9 projected, +0.5)||4.88|
|2014.04||143.9||144.8||84.7||(77.0 projected, -0.9)||7.88|
|2014.05||139.9 (1)||38.5 (2A) / 118.8 (2B) / 98.7 (2C)||(74.4 projected, -2.6)||(6.7)|
1) Running average based on the daily 20:00 UTC observed solar flux value at
2A) Current impact on the monthly sunspot number based on the Boulder (NOAA/SWPC) sunspot number (accumulated daily sunspots / month days). The official WDC-SILSO international sunspot number is typically 30-50% lower. 2B) Boulder SN current month average to date. 2C) STAR SDO 1K Wolf number 30 day average.
3) Running average based on the quicklook and definitive Potsdam WDC ap indices. Values in red are based on the definitive international GFZ Potsdam WDC ap indices.
This report has been prepared by Jan Alvestad. It is based on the analysis of data from whatever sources are available at the time the report is prepared. All time references are to the UTC day. Comments and suggestions are always welcome.
SDO images are courtesy of NASA/SDO and the AIA, EVE, and HMI science teams.